Conductive brush and method of securing attachments thereto



Feb. 16,1926 1,573,402

, A. F. HERMAN ET AL CONDUCTIVE BRUSH AND METHOD OF SECURING ATTACHMENTS THERETO Filed May 19, 1924 6H0: cum

Patented Feb. 16, 1926.

UNITED STATES v 1,513,402 PATENT OFFICE.

ALBERT F. HERMAN, OF CLEVELAND, AND HORACE S. ELLSON, OF LAKEWOOD, OHIO, ASSIGNOBS TO NATIONAL CARBON COMPANY, INC., A CORPORATION OF NEW YORK.

CONDUCTIVE BRUSH AND METHOD OF SECURING ATTACHMENTS THERETO.

Application filed May 19, 1924. Serial No. 714,496.

To all 'wkom'it may concern:

Be it known that we, ALBERT F. HERMAN and HORACE S. ELLsoN, citizens of the United States, res.ding at Cleveland and Lakewood, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Conductive Brushes and Methods of Securing Attach ments Ihereto, of which the following is a specification.

This invention relates to improvements in the-attachment of metallic members to conductive brushes for dynamo electric machines. The invention comprises the casting of a metallic cap or sheath about a portion of the brush, in such manner as to secure one or more flexible conductors or shunts in permanent, low resistance electrical contact with the brush. A finger piece for lifting the' brush, a rest for the spring hammer of thebrush holder, or the like, may be similarly secured.

The invention will be further described in connection with the accompanying drawings, in which Fig. 1 is a perspective view of a brush before the casting of the cap; I

Fig. .2 is a similar view, partly broken away, showing the cap, shunts and finger piece in position;

Fig. 3 is aperspective view, partly broken away, illustrating another form of brush having an electroplated coating on one end;

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Fig. 4 is a view similar to' Fig. 3, show- I Sing the completedbrush.

Referring to Figs. land 2, reference numeral 1 denotes a conductive brush which may be made of carbon, compacted metal powder,'or other"sui table material. The invention is particularly applicable to carbon brushes, as it provides a strong, low resisteases ance connection without the necessity of drilling, rivet ng, tampmg,-or the like, to fasten the shunt to the brush. Such procbonb cs.

The brush lhas a reduced up er ortion 2. Space for receiving the end 0 a s nut is rovided by beveling a corner of the -re-.

uced rtion. In the type shown, which is adapte .toihave two shunts 3. and 3' connected to it, spaces 4 and 5 are so provided. A groove 6 may be formed in the top of uently result in breakage of carthe brush to receive the base of a finger piece 7, or the like. This may be made of steel or iron, or of less rigid material, as a copper alloy. In the latter case suitable strengthening ribs or corrugations maybe provided.

, Openings 8 are preferably formed in the reduced portion of the brush. Some of the cast metal will flow into these openings and anchor the cap 9. The same result may be obtained in other ways, as by inclining the walls of the reduced portion inwardly.

The brush 10 shown in Figs. 3 and 4 has a cast cap 11 of the type previously described. It is, however, secured to the brush by union with an electroplated coating 12 applied to the reduced portion 13. Open lngs to receive the metal may be provided as in Fig. 1, but they are unnecessary under -most conditions. An electroplated coating of usual thickness is ordinarily adequate.

The cap may be formed of any suitable metal or alloy. Brass, aluminum-copper alloys, and the like, are especially adapted for this purpose.

The dies used for casting the ca of the usual die-casting type. best arranged to receive the brush, shunts, and other attachments before the molten may be metal is applied. It is preferable to force the metal into the die under high pressure, which maybe of the order of 1200 pounds per square inch. In this way a very hard, closely adherent ca is obtained. The exterior of the applie metal will be substantially flush with the lower surfaces of the brush, so that it may be inserted in the usual holders.

Brushes manufactured according to the present invention give excellent service; The shunt connections are substantially unafiected by vibration; The fin er pieces are also securely retained. Since 51c end of the shunt is practically an integral part of the cap, and the cap has. a large surface in in tima-te contact with the brush, the voltage drop between brush and shunt is negligib e.

Particularly low resistance contacts are obtained when the cap is cast about an elec- It is to noted that we eliminate sdlder, which has heretofore been used to secure ey are p abnormally hot, which may occur under certain service conditions. In the type of brush having metal cast about the end of a shunt inserted in a drilled opening, difficulty is, encountered in drilling and the metallic area in contact with the brush is low, as compared with the present construction.

The invention is not limited to the forms shown. Various modifications may be made in the shape of the brushes, the number and arrangement of shunts, the method of depositing the metal, and the like. Such modifications are within appended claims.

We claim: 1. In combination with a conductive brush, a conductor, and deposited metal the scope of the upon at least. a portion of the lateral 'exterior of said brush, said conductor havin an end embedded in said metal.

2. In combination with a conductive brush, a flexible conductor, and a cast metal cap about and integrally joined to a portion of the brush, said conductor having an end embedded in the cap. I

3. In combination with a conductive brush having an electroplated coating on a portion of its surface, a cast metal cap adherent to said coating, and a flexible conbedded in said cap.

5. In combination with a conductive brush, a cast metal cap integrally joined to said brush, and attachments embedded in said cap.

6.-A conductive brush having a reduced upper portion, a corner of which is cut away to receive the end of a flexible conductor, and a cast metal cap integrally joined to said reduced portion and embedding said conductor.

7. A conductive brush having a reduced upper portion, and a groove formed therein adapted to receive the end of an attachment, and a cast metal cap integrally joined to said upper portion and holding the end of the attachment inccontact with said brush.-

8. Method of securing an attachment to a; conductive brush, comprising depositing metal about an exterior portion of the brush and embedding an end of such attachment therein.

4 9. Method of securing a flexible conductor to a conductive brush, comprising inserting an end of the conductor in a lateral opening of the brush, and casting metal about such opening and a further portion of the brush.

10. Method of securing a. flexible conductor to a conductive brush, comprising die casting ametal'about a portion of the brush and flexible conductor.

11. Method of securing a flexible conductor to a conductive brush, comprising placing the brush in a die, inserting an end. of a flexible conductor in a recessed portion of the brush, and forcing a molten metal into the dieand about the brush and conductor.

In testimony whereof, we afiix our signatures.

ALBERT F. HERMAN. HORACE s. ELLSON. 

